The present invention relates generally to folding bed frames structures and, more particularly, to a novel folding bed frame structure and fabrication method having frictionally inter-fitting components assemblable without fasteners.
Folding bed frame structures of various configurations and constructions are well known and in widespread use, particularly in so-called sofa sleepers which basically comprise an upholstered sofa frame in which a folding bed frame structure is mounted for selective articulated movement between a folded condition fully contained within the sofa frame for seating use as a sofa and an unfolded condition extending outwardly from the sofa frame for sleeping use as a bed.
Conventionally folding bed frame structures used in sofa sleepers basically comprise a pair of laterally spaced side frame assemblies each formed of multiple pivoted or hinged frame components connected by various cross members for coordinated folding and unfolding movement between retracted and extended positions. Under traditional manufacturing techniques, the various cross members are rigidly affixed permanently to the two side frame assemblies by rivets or like fasteners typically installed by hydraulic or pneumatic riveting guns.
While this matter of construction and assembly of sofa sleeper bed frame structures has proven reliable in practice and the resultant folding bed frame structures had been demonstrated over time and usage to be of a stable and secure assembly, this matter of construction nevertheless presents several disadvantages. First, the use of rivets to assemble the various components makes the assembly operation relatively time consuming and labor intensive. The special riveting tools thusly required add to the capital outlay required of the manufacturer, and such tools pose an additional risk of potential injury to assembly workers. The fully assembled structure occupies a relatively large volume in relation to its total weight, which prevents efficient compact shipping, further adding to the total cost to the end user. Finally, the relative permanency of the riveted connections utilized makes it difficult and costly to replace defective or damaged components.
Conventional sofa sleeper bed frame structures characteristically utilize so-called "angle" members having an L-shaped cross-section for the side frame components, which provides advantages in the manufacturing process in that shorter rivets may be utilized to join to the "angle" components with lesser force required of the riveting tool while at the same time achieving a stronger rivet joint as compared to the alternative of utilizing tubular side frame components. However, many furniture manufacturers prefer the appearance of tubular components over "angle" components despite the structural advantages of the latter.